Its a shame that the Vita only has 128MB of VRAM. Perhaps had it been 256MB like the PS3 they could've had the same level of textures as the PS3 version. Furthermore, they probably could've turned on higher detail models/bump mapping during the Intros, X-Rays & Fatalities where 60 FPS wouldn't be necessary.
The Vita has more total ram then the PS3. Someone suggested on the other thread that it could also be a memory card size issue.